Fix example's BasicUnit array conversion.

QuLogic · QuLogic · commit 4cca44965c7c · 2021-02-18T00:05:22.000-05:00
A unit is a scalar, not a length-1 array. Though `BasicUnit` implements `__rmul__`, if multiplying by an array, the NumPy implementation will call `__array__` instead. If the LHS is an array, everything is fine, but if the LHS is a scalar, the previous code would incorrectly cause it to be upcast to a 1D array. When `__getitem__` was added in #19415, `np.atleast_1d` started iterating each (now 1D, not scalar) `TaggedValue`, seeing it was length 1, and made the x/y arrays into (N, 1) instead of (N,).
diff --git a/examples/units/basic_units.py b/examples/units/basic_units.py
@@ -218,7 +218,7 @@ def __array_wrap__(self, array, context):
         return TaggedValue(array, self)
 
     def __array__(self, t=None, context=None):
-        ret = np.array([1])
+        ret = np.array(1)
         if t is not None:
             return ret.astype(t)
         else:
